diff --git a/rtl/axis/taxi_axis_register.sv b/rtl/axis/taxi_axis_register.sv new file mode 100644 index 0000000..76180ae --- /dev/null +++ b/rtl/axis/taxi_axis_register.sv @@ -0,0 +1,256 @@ +// SPDX-License-Identifier: CERN-OHL-S-2.0 +/* + +Copyright (c) 2014-2025 FPGA Ninja, LLC + +Authors: +- Alex Forencich + +*/ + +`resetall +`timescale 1ns / 1ps +`default_nettype none + +/* + * AXI4-Stream register + */ +module taxi_axis_register # +( + // Register type + // 0 to bypass, 1 for simple buffer, 2 for skid buffer + parameter REG_TYPE = 2 +) +( + input wire logic clk, + input wire logic rst, + + /* + * AXI4-Stream input (sink) + */ + taxi_axis_if.snk s_axis, + + /* + * AXI4-Stream output (source) + */ + taxi_axis_if.src m_axis +); + +// extract parameters +localparam DATA_W = s_axis.DATA_W; +localparam logic KEEP_EN = s_axis.KEEP_EN && m_axis.KEEP_EN; +localparam KEEP_W = s_axis.KEEP_W; +localparam logic STRB_EN = s_axis.STRB_EN && m_axis.STRB_EN; +localparam logic LAST_EN = s_axis.LAST_EN && m_axis.LAST_EN; +localparam logic ID_EN = s_axis.ID_EN && m_axis.ID_EN; +localparam ID_W = s_axis.ID_W; +localparam logic DEST_EN = s_axis.DEST_EN && m_axis.DEST_EN; +localparam DEST_W = s_axis.DEST_W; +localparam logic USER_EN = s_axis.USER_EN && m_axis.USER_EN; +localparam USER_W = s_axis.USER_W; + +// check configuration +if (m_axis.DATA_W != DATA_W) + $fatal(0, "Error: Interface DATA_W parameter mismatch (instance %m)"); + +if (KEEP_EN && m_axis.KEEP_W != KEEP_W) + $fatal(0, "Error: Interface KEEP_W parameter mismatch (instance %m)"); + +if (REG_TYPE > 1) begin + // skid buffer, no bubble cycles + + // datapath registers + logic s_axis_tready_reg = 1'b0; + + logic [DATA_W-1:0] m_axis_tdata_reg = '0; + logic [KEEP_W-1:0] m_axis_tkeep_reg = '0; + logic [KEEP_W-1:0] m_axis_tstrb_reg = '0; + logic m_axis_tvalid_reg = 1'b0, m_axis_tvalid_next; + logic m_axis_tlast_reg = 1'b0; + logic [ID_W-1:0] m_axis_tid_reg = '0; + logic [DEST_W-1:0] m_axis_tdest_reg = '0; + logic [USER_W-1:0] m_axis_tuser_reg = '0; + + logic [DATA_W-1:0] temp_m_axis_tdata_reg = '0; + logic [KEEP_W-1:0] temp_m_axis_tkeep_reg = '0; + logic [KEEP_W-1:0] temp_m_axis_tstrb_reg = '0; + logic temp_m_axis_tvalid_reg = 1'b0, temp_m_axis_tvalid_next; + logic temp_m_axis_tlast_reg = 1'b0; + logic [ID_W-1:0] temp_m_axis_tid_reg = '0; + logic [DEST_W-1:0] temp_m_axis_tdest_reg = '0; + logic [USER_W-1:0] temp_m_axis_tuser_reg = '0; + + // datapath control + logic store_axis_input_to_output; + logic store_axis_input_to_temp; + logic store_axis_temp_to_output; + + assign s_axis.tready = s_axis_tready_reg; + + assign m_axis.tdata = m_axis_tdata_reg; + assign m_axis.tkeep = KEEP_EN ? m_axis_tkeep_reg : '1; + assign m_axis.tstrb = STRB_EN ? m_axis_tstrb_reg : s_axis.tkeep; + assign m_axis.tvalid = m_axis_tvalid_reg; + assign m_axis.tlast = LAST_EN ? m_axis_tlast_reg : 1'b1; + assign m_axis.tid = ID_EN ? m_axis_tid_reg : '0; + assign m_axis.tdest = DEST_EN ? m_axis_tdest_reg : '0; + assign m_axis.tuser = USER_EN ? m_axis_tuser_reg : '0; + + // enable ready input next cycle if output is ready or the temp reg will not be filled on the next cycle (output reg empty or no input) + wire s_axis_tready_early = m_axis.tready || (!temp_m_axis_tvalid_reg && (!m_axis_tvalid_reg || !s_axis.tvalid)); + + always_comb begin + // transfer sink ready state to source + m_axis_tvalid_next = m_axis_tvalid_reg; + temp_m_axis_tvalid_next = temp_m_axis_tvalid_reg; + + store_axis_input_to_output = 1'b0; + store_axis_input_to_temp = 1'b0; + store_axis_temp_to_output = 1'b0; + + if (s_axis_tready_reg) begin + // input is ready + if (m_axis.tready || !m_axis_tvalid_reg) begin + // output is ready or currently not valid, transfer data to output + m_axis_tvalid_next = s_axis.tvalid; + store_axis_input_to_output = 1'b1; + end else begin + // output is not ready, store input in temp + temp_m_axis_tvalid_next = s_axis.tvalid; + store_axis_input_to_temp = 1'b1; + end + end else if (m_axis.tready) begin + // input is not ready, but output is ready + m_axis_tvalid_next = temp_m_axis_tvalid_reg; + temp_m_axis_tvalid_next = 1'b0; + store_axis_temp_to_output = 1'b1; + end + end + + always_ff @(posedge clk) begin + s_axis_tready_reg <= s_axis_tready_early; + m_axis_tvalid_reg <= m_axis_tvalid_next; + temp_m_axis_tvalid_reg <= temp_m_axis_tvalid_next; + + // datapath + if (store_axis_input_to_output) begin + m_axis_tdata_reg <= s_axis.tdata; + m_axis_tkeep_reg <= s_axis.tkeep; + m_axis_tstrb_reg <= s_axis.tstrb; + m_axis_tlast_reg <= s_axis.tlast; + m_axis_tid_reg <= s_axis.tid; + m_axis_tdest_reg <= s_axis.tdest; + m_axis_tuser_reg <= s_axis.tuser; + end else if (store_axis_temp_to_output) begin + m_axis_tdata_reg <= temp_m_axis_tdata_reg; + m_axis_tkeep_reg <= temp_m_axis_tkeep_reg; + m_axis_tstrb_reg <= temp_m_axis_tstrb_reg; + m_axis_tlast_reg <= temp_m_axis_tlast_reg; + m_axis_tid_reg <= temp_m_axis_tid_reg; + m_axis_tdest_reg <= temp_m_axis_tdest_reg; + m_axis_tuser_reg <= temp_m_axis_tuser_reg; + end + + if (store_axis_input_to_temp) begin + temp_m_axis_tdata_reg <= s_axis.tdata; + temp_m_axis_tkeep_reg <= s_axis.tkeep; + temp_m_axis_tstrb_reg <= s_axis.tstrb; + temp_m_axis_tlast_reg <= s_axis.tlast; + temp_m_axis_tid_reg <= s_axis.tid; + temp_m_axis_tdest_reg <= s_axis.tdest; + temp_m_axis_tuser_reg <= s_axis.tuser; + end + + if (rst) begin + s_axis_tready_reg <= 1'b0; + m_axis_tvalid_reg <= 1'b0; + temp_m_axis_tvalid_reg <= 1'b0; + end + end + +end else if (REG_TYPE == 1) begin + // simple register, inserts bubble cycles + + // datapath registers + logic s_axis_tready_reg = 1'b0; + + logic [DATA_W-1:0] m_axis_tdata_reg = '0; + logic [KEEP_W-1:0] m_axis_tkeep_reg = '0; + logic [KEEP_W-1:0] m_axis_tstrb_reg = '0; + logic m_axis_tvalid_reg = 1'b0, m_axis_tvalid_next; + logic m_axis_tlast_reg = 1'b0; + logic [ID_W-1:0] m_axis_tid_reg = '0; + logic [DEST_W-1:0] m_axis_tdest_reg = '0; + logic [USER_W-1:0] m_axis_tuser_reg = '0; + + // datapath control + logic store_axis_input_to_output; + + assign s_axis.tready = s_axis_tready_reg; + + assign m_axis.tdata = m_axis_tdata_reg; + assign m_axis.tkeep = KEEP_EN ? m_axis_tkeep_reg : '1; + assign m_axis.tstrb = STRB_EN ? s_axis.tstrb : s_axis.tkeep; + assign m_axis.tvalid = m_axis_tvalid_reg; + assign m_axis.tlast = LAST_EN ? m_axis_tlast_reg : 1'b1; + assign m_axis.tid = ID_EN ? m_axis_tid_reg : '0; + assign m_axis.tdest = DEST_EN ? m_axis_tdest_reg : '0; + assign m_axis.tuser = USER_EN ? m_axis_tuser_reg : '0; + + // enable ready input next cycle if output buffer will be empty + wire s_axis_tready_early = !m_axis_tvalid_next; + + always_comb begin + // transfer sink ready state to source + m_axis_tvalid_next = m_axis_tvalid_reg; + + store_axis_input_to_output = 1'b0; + + if (s_axis_tready_reg) begin + m_axis_tvalid_next = s_axis.tvalid; + store_axis_input_to_output = 1'b1; + end else if (m_axis.tready) begin + m_axis_tvalid_next = 1'b0; + end + end + + always_ff @(posedge clk) begin + s_axis_tready_reg <= s_axis_tready_early; + m_axis_tvalid_reg <= m_axis_tvalid_next; + + // datapath + if (store_axis_input_to_output) begin + m_axis_tdata_reg <= s_axis.tdata; + m_axis_tkeep_reg <= s_axis.tkeep; + m_axis_tstrb_reg <= s_axis.tstrb; + m_axis_tlast_reg <= s_axis.tlast; + m_axis_tid_reg <= s_axis.tid; + m_axis_tdest_reg <= s_axis.tdest; + m_axis_tuser_reg <= s_axis.tuser; + end + + if (rst) begin + s_axis_tready_reg <= 1'b0; + m_axis_tvalid_reg <= 1'b0; + end + end + +end else begin + // bypass + + assign m_axis.tdata = s_axis.tdata; + assign m_axis.tkeep = KEEP_EN ? s_axis.tkeep : '1; + assign m_axis.tstrb = STRB_EN ? s_axis.tstrb : s_axis.tkeep; + assign m_axis.tvalid = s_axis.tvalid; + assign m_axis.tlast = LAST_EN ? s_axis.tlast : 1'b1; + assign m_axis.tid = ID_EN ? s_axis.tid : '0; + assign m_axis.tdest = DEST_EN ? s_axis.tdest : '0; + assign m_axis.tuser = USER_EN ? s_axis.tuser : '0; + + assign s_axis.tready = m_axis.tready; + +end + +endmodule + +`resetall diff --git a/tb/axis/taxi_axis_register/Makefile b/tb/axis/taxi_axis_register/Makefile new file mode 100644 index 0000000..1852d1c --- /dev/null +++ b/tb/axis/taxi_axis_register/Makefile @@ -0,0 +1,59 @@ +# SPDX-License-Identifier: CERN-OHL-S-2.0 +# +# Copyright (c) 2021-2025 FPGA Ninja, LLC +# +# Authors: +# - Alex Forencich + +TOPLEVEL_LANG = verilog + +SIM ?= verilator +WAVES ?= 0 + +COCOTB_HDL_TIMEUNIT = 1ns +COCOTB_HDL_TIMEPRECISION = 1ps + +DUT = taxi_axis_register +COCOTB_TEST_MODULES = test_$(DUT) +COCOTB_TOPLEVEL = test_$(DUT) +MODULE = $(COCOTB_TEST_MODULES) +TOPLEVEL = $(COCOTB_TOPLEVEL) +VERILOG_SOURCES += $(COCOTB_TOPLEVEL).sv +VERILOG_SOURCES += ../../../rtl/axis/$(DUT).sv +VERILOG_SOURCES += ../../../rtl/axis/taxi_axis_if.sv + +# handle file list files +process_f_file = $(call process_f_files,$(addprefix $(dir $1),$(shell cat $1))) +process_f_files = $(foreach f,$1,$(if $(filter %.f,$f),$(call process_f_file,$f),$f)) +uniq_base = $(if $1,$(call uniq_base,$(foreach f,$1,$(if $(filter-out $(notdir $(lastword $1)),$(notdir $f)),$f,))) $(lastword $1)) +VERILOG_SOURCES := $(call uniq_base,$(call process_f_files,$(VERILOG_SOURCES))) + +# module parameters +export PARAM_DATA_W := 8 +export PARAM_KEEP_EN := $(shell echo $$(( $(PARAM_DATA_W) > 8 ))) +export PARAM_KEEP_W := $(shell echo $$(( ( $(PARAM_DATA_W) + 7 ) / 8 ))) +export PARAM_STRB_EN := 0 +export PARAM_DEPTH := $(shell echo $$(( 1024 * $(PARAM_KEEP_W) ))) +export PARAM_LAST_EN := 1 +export PARAM_ID_EN := 1 +export PARAM_ID_W := 8 +export PARAM_DEST_EN := 1 +export PARAM_DEST_W := 8 +export PARAM_USER_EN := 1 +export PARAM_USER_W := 1 +export PARAM_REG_TYPE := 2 + +ifeq ($(SIM), icarus) + PLUSARGS += -fst + + COMPILE_ARGS += $(foreach v,$(filter PARAM_%,$(.VARIABLES)),-P $(COCOTB_TOPLEVEL).$(subst PARAM_,,$(v))=$($(v))) +else ifeq ($(SIM), verilator) + COMPILE_ARGS += $(foreach v,$(filter PARAM_%,$(.VARIABLES)),-G$(subst PARAM_,,$(v))=$($(v))) + + ifeq ($(WAVES), 1) + COMPILE_ARGS += --trace-fst + VERILATOR_TRACE = 1 + endif +endif + +include $(shell cocotb-config --makefiles)/Makefile.sim diff --git a/tb/axis/taxi_axis_register/test_taxi_axis_register.py b/tb/axis/taxi_axis_register/test_taxi_axis_register.py new file mode 100644 index 0000000..3e942c0 --- /dev/null +++ b/tb/axis/taxi_axis_register/test_taxi_axis_register.py @@ -0,0 +1,258 @@ +#!/usr/bin/env python +# SPDX-License-Identifier: CERN-OHL-S-2.0 +""" + +Copyright (c) 2021-2025 FPGA Ninja, LLC + +Authors: +- Alex Forencich + +""" + +import itertools +import logging +import os +import random + +import cocotb_test.simulator +import pytest + +import cocotb +from cocotb.clock import Clock +from cocotb.triggers import RisingEdge +from cocotb.regression import TestFactory + +from cocotbext.axi import AxiStreamBus, AxiStreamFrame, AxiStreamSource, AxiStreamSink + + +class TB(object): + def __init__(self, dut): + self.dut = dut + + self.log = logging.getLogger("cocotb.tb") + self.log.setLevel(logging.DEBUG) + + cocotb.start_soon(Clock(dut.clk, 10, units="ns").start()) + + self.source = AxiStreamSource(AxiStreamBus.from_entity(dut.s_axis), dut.clk, dut.rst) + self.sink = AxiStreamSink(AxiStreamBus.from_entity(dut.m_axis), dut.clk, dut.rst) + + def set_idle_generator(self, generator=None): + if generator: + self.source.set_pause_generator(generator()) + + def set_backpressure_generator(self, generator=None): + if generator: + self.sink.set_pause_generator(generator()) + + async def reset(self): + self.dut.rst.setimmediatevalue(0) + await RisingEdge(self.dut.clk) + await RisingEdge(self.dut.clk) + self.dut.rst.value = 1 + await RisingEdge(self.dut.clk) + await RisingEdge(self.dut.clk) + self.dut.rst.value = 0 + await RisingEdge(self.dut.clk) + await RisingEdge(self.dut.clk) + + +async def run_test(dut, payload_lengths=None, payload_data=None, idle_inserter=None, backpressure_inserter=None): + + tb = TB(dut) + + id_count = 2**len(tb.source.bus.tid) + + cur_id = 1 + + await tb.reset() + + tb.set_idle_generator(idle_inserter) + tb.set_backpressure_generator(backpressure_inserter) + + test_frames = [] + + for test_data in [payload_data(x) for x in payload_lengths()]: + test_frame = AxiStreamFrame(test_data) + test_frame.tid = cur_id + test_frame.tdest = cur_id + + test_frames.append(test_frame) + await tb.source.send(test_frame) + + cur_id = (cur_id + 1) % id_count + + for test_frame in test_frames: + rx_frame = await tb.sink.recv() + + assert rx_frame.tdata == test_frame.tdata + assert rx_frame.tid == test_frame.tid + assert rx_frame.tdest == test_frame.tdest + assert not rx_frame.tuser + + assert tb.sink.empty() + + await RisingEdge(dut.clk) + await RisingEdge(dut.clk) + + +async def run_test_tuser_assert(dut): + + tb = TB(dut) + + await tb.reset() + + test_data = bytearray(itertools.islice(itertools.cycle(range(256)), 32)) + test_frame = AxiStreamFrame(test_data, tuser=1) + await tb.source.send(test_frame) + + rx_frame = await tb.sink.recv() + + assert rx_frame.tdata == test_data + assert rx_frame.tuser + + assert tb.sink.empty() + + await RisingEdge(dut.clk) + await RisingEdge(dut.clk) + + +async def run_stress_test(dut, idle_inserter=None, backpressure_inserter=None): + + tb = TB(dut) + + byte_lanes = tb.source.byte_lanes + id_count = 2**len(tb.source.bus.tid) + + cur_id = 1 + + await tb.reset() + + tb.set_idle_generator(idle_inserter) + tb.set_backpressure_generator(backpressure_inserter) + + test_frames = [] + + for k in range(128): + length = random.randint(1, byte_lanes*16) + test_data = bytearray(itertools.islice(itertools.cycle(range(256)), length)) + test_frame = AxiStreamFrame(test_data) + test_frame.tid = cur_id + test_frame.tdest = cur_id + + test_frames.append(test_frame) + await tb.source.send(test_frame) + + cur_id = (cur_id + 1) % id_count + + for test_frame in test_frames: + rx_frame = await tb.sink.recv() + + assert rx_frame.tdata == test_frame.tdata + assert rx_frame.tid == test_frame.tid + assert rx_frame.tdest == test_frame.tdest + assert not rx_frame.tuser + + assert tb.sink.empty() + + await RisingEdge(dut.clk) + await RisingEdge(dut.clk) + + +def cycle_pause(): + return itertools.cycle([1, 1, 1, 0]) + + +def size_list(): + data_width = len(cocotb.top.m_axis.tdata) + byte_width = data_width // 8 + return list(range(1, byte_width*4+1))+[512]+[1]*64 + + +def incrementing_payload(length): + return bytearray(itertools.islice(itertools.cycle(range(256)), length)) + + +if cocotb.SIM_NAME: + + factory = TestFactory(run_test) + factory.add_option("payload_lengths", [size_list]) + factory.add_option("payload_data", [incrementing_payload]) + factory.add_option("idle_inserter", [None, cycle_pause]) + factory.add_option("backpressure_inserter", [None, cycle_pause]) + factory.generate_tests() + + for test in [run_test_tuser_assert]: + factory = TestFactory(test) + factory.generate_tests() + + factory = TestFactory(run_stress_test) + factory.add_option("idle_inserter", [None, cycle_pause]) + factory.add_option("backpressure_inserter", [None, cycle_pause]) + factory.generate_tests() + + +# cocotb-test + +tests_dir = os.path.dirname(__file__) +rtl_dir = os.path.abspath(os.path.join(tests_dir, '..', '..', '..', 'rtl')) + + +def process_f_files(files): + lst = {} + for f in files: + if f[-2:].lower() == '.f': + with open(f, 'r') as fp: + l = fp.read().split() + for f in process_f_files([os.path.join(os.path.dirname(f), x) for x in l]): + lst[os.path.basename(f)] = f + else: + lst[os.path.basename(f)] = f + return list(lst.values()) + + +@pytest.mark.parametrize("reg_type", [0, 1, 2]) +@pytest.mark.parametrize("data_w", [8, 16, 32]) +def test_taxi_axis_register(request, data_w, reg_type): + dut = "taxi_axis_register" + module = os.path.splitext(os.path.basename(__file__))[0] + toplevel = module + + verilog_sources = [ + os.path.join(tests_dir, f"{toplevel}.sv"), + os.path.join(rtl_dir, "axis", f"{dut}.sv"), + os.path.join(rtl_dir, "axis", "taxi_axis_if.sv"), + ] + + verilog_sources = process_f_files(verilog_sources) + + parameters = {} + + parameters['DATA_W'] = data_w + parameters['KEEP_EN'] = int(parameters['DATA_W'] > 8) + parameters['KEEP_W'] = (parameters['DATA_W'] + 7) // 8 + parameters['STRB_EN'] = 0 + parameters['LAST_EN'] = 1 + parameters['ID_EN'] = 1 + parameters['ID_W'] = 8 + parameters['DEST_EN'] = 1 + parameters['DEST_W'] = 8 + parameters['USER_EN'] = 1 + parameters['USER_W'] = 1 + parameters['REG_TYPE'] = reg_type + + extra_env = {f'PARAM_{k}': str(v) for k, v in parameters.items()} + + sim_build = os.path.join(tests_dir, "sim_build", + request.node.name.replace('[', '-').replace(']', '')) + + cocotb_test.simulator.run( + simulator="verilator", + python_search=[tests_dir], + verilog_sources=verilog_sources, + toplevel=toplevel, + module=module, + parameters=parameters, + sim_build=sim_build, + extra_env=extra_env, + ) diff --git a/tb/axis/taxi_axis_register/test_taxi_axis_register.sv b/tb/axis/taxi_axis_register/test_taxi_axis_register.sv new file mode 100644 index 0000000..45a33ec --- /dev/null +++ b/tb/axis/taxi_axis_register/test_taxi_axis_register.sv @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: CERN-OHL-S-2.0 +/* + +Copyright (c) 2025 FPGA Ninja, LLC + +Authors: +- Alex Forencich + +*/ + +`resetall +`timescale 1ns / 1ps +`default_nettype none + +/* + * AXI4-Stream register testbench + */ +module test_taxi_axis_register # +( + /* verilator lint_off WIDTHTRUNC */ + parameter DEPTH = 4096, + parameter DATA_W = 8, + parameter logic KEEP_EN = (DATA_W>8), + parameter KEEP_W = ((DATA_W+7)/8), + parameter logic STRB_EN = 1'b0, + parameter logic LAST_EN = 1'b1, + parameter logic ID_EN = 1'b0, + parameter ID_W = 8, + parameter logic DEST_EN = 1'b0, + parameter DEST_W = 8, + parameter logic USER_EN = 1'b1, + parameter USER_W = 1, + parameter REG_TYPE = 2 + /* verilator lint_on WIDTHTRUNC */ +) +(); + +logic clk; +logic rst; + +taxi_axis_if #( + .DATA_W(DATA_W), + .KEEP_EN(KEEP_EN), + .KEEP_W(KEEP_W), + .STRB_EN(STRB_EN), + .LAST_EN(LAST_EN), + .ID_EN(ID_EN), + .ID_W(ID_W), + .DEST_EN(DEST_EN), + .DEST_W(DEST_W), + .USER_EN(USER_EN), + .USER_W(USER_W) +) s_axis(), m_axis(); + +taxi_axis_register #( + .REG_TYPE(REG_TYPE) +) +uut ( + .clk(clk), + .rst(rst), + + /* + * AXI4-Stream input (sink) + */ + .s_axis(s_axis), + + /* + * AXI4-Stream output (source) + */ + .m_axis(m_axis) +); + +endmodule + +`resetall